This invention relates to a sanitary napkin for personal feminine care which absorbs menstrual fluids or similar exudates.
Japanese Patent Application Disclosure Gazette (Kokai) No. Hei2-11138 discloses a sanitary napkin provided with bending means referred to as xe2x80x9cdeformation inducing elementxe2x80x9d adapted to deform the sanitary napkin so that its side facing a wearer""s body may be curved convexly upward when the sanitary napkin is put on the wearer""s body. Such a deformation inducing means is a formed material such polyethylene foam, other plastic sheet or cardboard having substantially the same size as that of the sanitary napkin. An absorbent core of the sanitary napkin and a backsheet covering a lower surface of the absorbent core are in close contact with the deformation inducing element and are deformed together with the deformation inducing element to form a convex curve.
With the element functioning to induce a convex deformation of the sanitary napkin normally kept in close contact with the lower surface of the absorbent core directly or indirectly with interposition of the backsheet as in the case of the above-mentioned sanitary napkin, a thickness of the deformation inducing element is added to a thickness of the absorbent core itself. Consequently, the absorbent core can not offer a breathability in the direction of its thickness sufficient to avoid a stuffiness from which the wearer might suffer when she wears the sanitary napkin.
It is an object of the present invention to provide a sanitary napkin provided on its lower side with a pad serving to hold the absorbent core in its shape curved convexly toward a body-facing side without deteriorating a breathability desired for the sanitary napkin.
According to the present invention, there is provided a sanitary napkin having a longitudinal direction and a transverse direction, the sanitary napkin comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between the topsheet and the backsheet, a cross-section of the absorbent core cut along the transverse direction being curved convexly toward a body-facing side and a pad curved convexly toward the body-facing side substantially in conformity with the absorbent core being placed against a lower surface of the absorbent core in a curved zone thereof wherein:
the surface of the pad placed against the absorbent core is composed of a plurality of intermittently arranged projections and a continuous trough comprising a plurality of trough sections each defined between each pair of the adjacent projections so that the trough sections extend longitudinally as well as transversely of the absorbent core to intersect one another and opposite ends of each trough section terminate at a peripheral edge of the pad, and the pad is placed against the lower surface of the absorbent core at tops of the projections so that a plurality of tunnel sections each having opposite ends thereof opened at the peripheral edge of the pad are formed between the continuous trough and the lower surface of the absorbent core.
According to one embodiment of the present invention, the pad lies in the transversely middle zone of the sanitary napkin so that imaginary lines extending in parallel to a center line dividing a width of the sanitary napkin in two are alternately interrupted by the projections and through of the pad.
According to another embodiment of the present invention, the pad is made of thermoplastic synthetic fibers.
According to still another embodiment of the present invention, the pad is made of crimped thermoplastic conjugated fibers.
According to yet another embodiment of the present invention, the pad is made of thermoplastic hollow fibers.
According to further another embodiment of the present invention, a height as measured from a bottom of the trough to a top of the projection is 0.3xcx9c3 mm.
According to another embodiment of the present invention, the trough rectilinearly extends obliquely across the longitudinal direction of the absorbent core.
According to still another embodiment of the present invention, the trough meanders so as to obliquely intersect the longitudinal direction of the absorbent core.
According to yet another embodiment of the present invention, the pad is relatively thick at the projections and relatively thin at the trough.
According to further another embodiment of the present invention, the pad is made of thermoplastic synthetic fibers, having a relatively low density at the projections and a relatively high density at the trough.
According to an additional embodiment of the present invention, the pad, in its transversely curved state, presents a rigidity gradually decreasing from its transversely middle zone to its transversely opposite side edges.
According to still additional embodiment of the present invention, the pad is made of a foamed plastic sheet.
According to further additional embodiment of the present invention, the pad is made of a compressed foam plastic sheet.